Engine



A June27, 1944. I c. G. A. ROSEN' ETAL 2,352,497

- ENGINE Filed Oct. 1, 1945 4 Sheets-Sheet 1 i I June 27, 1944. 7 Q RQSEN A 2,352,497

ENGINE Filed Oct. 1, 1943 fisheets-sheet 5 EI E Z4 24 A. 4- INVENTORS.

Carl 6.0. Rasen (arl 2. Max wel/ Patented June 27, 1944 Carl G. A. Rosen, Peoria, and Carl R. Maxwell, assignors to Caterpillar Tractor 00., San Leandro, Callt, a corporation Washington,

of California Application omen- 1, 1943,'Serial a... 504,552

11 Claims.

Our invention relates to internal combustion engines, and more particularly to the cooling of pistons in a compression ignition or Diesel en- -gine.

In a compression ignition engine, the pistons are usually of odd shape, and the heat of combustion is not, generally, immediately uniformly distributed in the main combustion chamber of the engine, as is the case with respect to a spark ignition internal combustion engine. Therefore,

to minimize hot spots and provide for adequate cooling, it is desirable to cool the pistons by a cooling fluid, such as the oil employed in lubrication of the engine. Such cooling of the pistons also enables the wall thicknesses at areas at which heat is concentrated by injection of fuelthereagainst, to be made thinner than would otherwise be the case, thus permitting reduction in weight which is an important factor.

Objects of our invention, among others, are the provision of an'improved piston cooling arsupplied against the piston. independent of inertia ellects that would occur by having passages for the cooling fluid in the connecting rod for the piston; which is particularly adapted for employment with an engine of the radial type, especially a-radia'l compression ignition engine; and which is of a relatively simple construction. Other objects of our invention will become apparent from a perusal of description thereof.

Referring to the drawings:

Flg.-8 is a fragmentary sectiontaken in a plane indicated by line 88 in Fig. 'l.

Theengine illustrated is a-radial Diesel or compression ignition engine of the type disclosed in our assigneefs copending application by Lloyd E. Johnson and Carl R. Maxwell, Serial No. 499,892, flied August 25, 194.3. However, it is to be understood that the featuresof our invention, although particularly adapted for a compression ignition engine, may be mployed in other types of internal combustion engines. As illustrated, the engine includes annular crankcase member 2 having peripherally disposed aircooled cylinders 3 detachably mounted thereon. Air-cooled heads I are detachably connected to the outer ends of the cylinders; and on each of such heads is mounted an air-cooled auxiliary combustion chamber 6 in the form of a prerangement wherein cooling 'fluid is continuously the following Fig. 1 is a fragmentary, partially schematic,

end view of a form of radial internal combus-- Fig. 3 is a sectional elevational view, also partially schematic, taken in a plane indicated by line 3-3 in Fig. 2.

Fig. 4 is an enlarged fragmentary section taken in a plane indicated by line 4-4 in Fig. 3.

Fig. 5 is an enlarged fragmentary section. taken in a plane indicated by line 5-5 in Fig. 2.

tional parts on the engine but taken in planesdifferent from the planes of Fig. 2, as is indicate by line in Figs. 1 and 3.

combustion chamber, and in which is seated fuel bustion chamber ll of each cylinder through I orifices l2 formed in the inner end of each precombustion chamber. As can be noted from Figs.

3 and l, the crown of working piston IS in each cylinderis of an odd shape, in that it is not symmetrical about a center point; and combus tible fuel is introduced into the main combus tion chamber Ii off-center with respect to the center of the crown. As a result, the crown or the piston would ordinarily-have a hot spot which the cooling system of our invention isdesigned to obviate as will be described hereinafter.

As is usual in radial engines, one of the pistons is connected to a master connecting rod ll con-. nected to crankshaft ii of the engine; while the otherpistons are connected in the usual manner to connecting, link rods i'i. With reference to Figs. 3 and '7, each rod is connected to an associated piston, by meanslof a wrist pin ll secured in spaced bosses l8 integral with the inner side 20 of the crown of the associated piston ll. Preferably, the inside wall oi the piston is grooved at 2| to provide cooling iins.

Detachably connected to an end of crankcase 2 is a nosepiece member 22 on which fuel injection pumps I are supported, and. which also sup ports reciprocatable valve tappetfollowers 23 for actuating valves 24 through suitable. push rods 26, only a portion 0! which appear in Fig. 7. For distributing lubricant to various parts of the en- .gine that have to be lubricated, including valve tappet followers 23, an annular interiormanifold 40 pounds per square inch.

passagefl is formed in nosepiece 22, to which are connected feed passages 22, in the nosepiece,

' being clamped between nosepiece 22 and crank case 2 to seal oi! manifoldpassage 21.

Lubricant is conducted to manifold passage, 21, by a passageway 3| formed in nosepiece 22, and which is connected to an exterior conduit or piping 32, by threaded coupling or fitting 32 of any suitable construction. Such piping 32 is bent, as is illustrated in Fig. 1, and is also connected to a means of lubricant supply, by a suitable elbow coupling or fitting 34 in turn screwed in a coupling elbow 36 which is connected to annular-like oil distributing manifold conduit or piping 21 mounted on nosepiece 22, exteriorly of the engine or without crankcase 2. Brackets 38, detachably secured to the nosepiece adjacent one end and fastened to exterior manifold 31 by suitable means such as welding, Provide the. support for manifold ,31 on the engine. Manifold 31 not only provides a' means for supplying oil to interior manifold 21, but also provides a means for distributing lubricant-for cooling of the pistons, in a manner to be described. a

A continuous supply of'lubricating oil is conducted to manifold 31, as long as the engine is running, by a suitable lubricant supply pump (not shown), commonly employed in an engine of the type described, for force feeding of lubricant. Such pump feeds the lubricant at a pressure of about 80 pounds per square inch, to a supply pipe 3| connected therewith, and to the coupling elbow it by fitting ii. The described pressure is desired in the particular engine in which our installation is now employed because some of the engine parts are best lubricated at this pressure. However, in such engine, it is desirable that the tity of injected oil will wash against inner side 20 of the piston crown. Aspray which will diffuse, will not perform this function because some of the cooling oil will hit the peripheral wall of the, piston-and also the cylinder wall. In this connection, Jet 48 is directed at the location on piston crown adjacent which the combustible fluid is introduced from auxiliary combustion chamber 6, to provide quick dissipation of heat from such portion of the piston crown at which the highest temperatures tend to occur.

To provide for proper directing of cooling 011 Jet 48, means is provided for fixedly securing or holding piping 44 to crankcase 2, and to hold jet part 41 thereof against turning. For this purpose, piping 44 is formed essentially, in two parts, namely the outwardly bent jet part 41,

and an inlet part 54. Jet part 41 is formed with a flange or shoulder 56 adapted to engage the inner side of crankcase rim 46, and with a screwthreaded portion 51 which projects exteriorly of the rim; jam or lock nuts 58 being screwed on portion 51 to clamp jet part 41 to the crankcase. For precluding angular turning of such jet part, a locking pin 59 is inserted in a groove, a part of which is formed in the wall of jet part 41 and another part of which is formed in the adjacent pressure of the oil in manifold 31, which is also employed to cool the pistons, be at a lesser pressure. For this reason, we preferably provide in coupling elbow SI adjacent supply pipe 30,- a ring member 42 having a pressure reducing orifice 41 of a size designed to reduce the pressure to about Associated with each cylinder of the engine is a conduit or piping 44 connected to manifold I1,

and which provides a feed line for directing oil against the inner side 20 of the piston crown to cool the same. As can be seen more clearly from Fig. 2, each of feed lines 44 is connected at one end to manifold 31, by a suitable coupling or fitting 4|, and is bent exteriorly of the engine to enable projection or extension thereof through -a jet-type discharge outlet orifice II, which diroots the cooling oil in a substantially solid un- 1 broken stream or Jet (in contradistinction to a spray) at a predetermined location on the inner side 2| of the piston crown. It is desirable that wall surface of the crankcase rim 46. Inlet part 54 is detachably connected to screw-threaded portion 51 of jet part 41., by a suitable coupling or fitting 6 i. 4

From the preceding, it is seen that piping, independent of any conduit passage formed in a connecting rod or link, is provided for introducing the cooling oil against the piston crown. This is important in insuring a steady continuous flow of cooling oil while the engine is running,

which might .not otherwise be the case were a conduit passage drilled in the connecting rod or link to conduct the cooling oil against the piston crown, because in the latter case the flow of oil would be effected by inertia eifects imparted to the connecting rod or link as it reciprocates. Also, with the arrangement of our invention, the

7 flow of oil is independentof crankshaft bearing the cooling oil be introduced against thepiston in pressure which is not the case where the oil is cogd'ucted through a passage in the connecting 'ro In addition, the independent piping is advantageous in a radial type of engine, wherein it is diflicult to form an adequate manifold adjacent the crankshaft for conducting the oil to passages in the connecting rods or links, because of the limited space in such'an engine. Another important factor of the arrangement of our invention, which makes for compactness, lies in the fact that exterior manifold 31 provides not only a distributing source for the feed lines directing the cooling oil against the pistons, but alsofor the feed line which is connected to interior manifold 21 which is utilized to conduct lubricating oil to other engine parts to be lubri cated.

. We claim:

1. In a radial internal combustion engine; a piston cooling system comprising an annularlike manifold for cooling fluid, and feed lines connected to the manifold for directing the cooling iluid to the pistons.

2. In an internal combustion engine including a member having cylinders and pistons within such cylinders;. a piston cooling system including a manifold for cooling fluidand which is mounted without said member, and feed lines connected to the manifold and extending into said member for directing the cooling fluid to the pistons.

3. In an internal combustion engine including a member having cylinders and pistons within such cylinders; a piston cooling system including a manifold pipefor cooling fluid and which is mounted without said member, feed lines connected to said manifold and extending into said member for directing the cooling fluid to the pistons, and means for fixedly securing said lines to said member.

' 4. In an internal combustion engine including a member having cylinders and pistons within such cylinders; a piston cooling system including a manifold for receiving oil, feed lines connected to said manifold for directing the oil to the pistons, a second manifold for oil to be conducted to other engine parts to be lubricated, and a line for conducting oil from said first mentioned manifold to said second manifold.

5. In a radial internal combustion engine having a crankcase member, a plurality of cylinders disposed about the crankcase member, and pistons within the cylinders; a piston oil cooling system comprising an annular-like manifold pipe for oil and which is mounted on the engine without the crankcase member, feed lines connected to the manifold each having a portion extending into the crankcase member and having an outlet for directing oil against an associated piston, and means fixedly holding each of said feed lines on the crankcase member.

adjacent the crankcase member, a plurality of cylinders disposed about the crankcase member and hav'ng their inner ends communicating with the inside of the crankcase member, and pistons within the cylinders; a piston oil coolingsys- ,tem comprising an exterior annular-like manifold pipe for oil, brackets secured to the nosepiece member for supporting such manifold, and feed lnes connected to the manifold each having a portion extending into the crankcase member for directing oil againstan associated piston.

9. In a radial internal combustion engine having a crankcase member, a nosepiece member 6.v In a radial internal combustionengine havfeed lines on the crankcase member against turning with respect thereto.

7. In a radial internal combustion engine having a crankcase member, a plurality of'cylinders disposed about the crankcase member, and pistons within the cylinders; -a piston oil cooling system comprising an annular-like manifold pipe for oil and which is mounted on the engine without the crankcase member, feed lines connected to the manifold each having a portion extending-into the crankcase member and having an outlet for directing oil against an-associated piston, an interior manifold for oil to be conducted to other engine parts to be lubricated,

and a line for conducting oil from said first mentioned manifold to said interior manifold.

8. In a radial internal combustion engine having a crankcase member, a nosepiece member .adjacent the crankcase member, a plurality. of

cylinders disposed about the crankcase member and having the r inner ends communicating with the inside of the crankcase member, and pistons wit in the cylinders; a piston oil cooling system comprising an exterior annular-like manifold pipe for oil, brackets secured to the nosepiece member for supporting such manifold, and feed lines connected to the manifold each-having a portion extending into the crankcase member for directing oil against an associated piston, one of "interior manifold.

10. A compression ignition or the like engine .naving a cylinder, a piston within the cylinder,

means for introducing combustible fuel into the cylinder adjacent a portion of the piston-crown, means for cooling the piston comprising a con du t member for continuously directingcooling fluid against the piston crown adjacent the portion thereof -at which fuel is introduced, said,

conduit means being adjacent the wall portion of the cylinder and independent of the connecting rod and wrist pin, and a jet-type discharge orifice mounted in the conduit means within the cylinder to direct the cooling fluid in a substantially unbroken stream against the piston.

11. A compression ignition or the like engine having a cylinder, a piston within the cylinder, means for introducing combustible fuel into the cylinder adjacent a portion of the piston crown, means for cooling the piston comprising a conduit member for continuously directing cooling flu d against the piston crown adjacent the portion thereof at which fuel is introduced. said conduit means being adjacent the wall portion of'the cylinder and independent of the connecting rod and wrist pin, a jet-type discharge orifice mounted in the conduit means within the I. cyl nder to direct the cooling fluid in a-substantially unbroken stream against the piston, and means between the discharge orifice and the conduit means to hold the discharge orifice against rotation in the conduit means.

cant. G. A. cam. R. MAXWELL. 

